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Theoretical Percent Included 130+ Very Superior 2.6 2.2 120–129 Superior 6.9 6.7 110–119 High Average 16.6 16.1 90–109 Average 49.1 50.0 80–89 Low Average 16.1 16.1 70–79 Borderline 6.4 6.7 below 70 Mentally Retarded 2.3 2.2
About 12.0 ± 3.3 Tmol of O 2 per year today goes to the sinks composed of reduced minerals and gases from volcanoes, metamorphism, percolating seawater and heat vents from the seafloor. [26] On the other hand, 5.7 ± 1.2 Tmol of O 2 per year today oxidizes reduced gases in the atmosphere through photochemical reaction. [ 26 ]
Rubidium ( 37 Rb) has 36 isotopes, with naturally occurring rubidium being composed of just two isotopes; 85 Rb (72.2%) and the radioactive 87 Rb (27.8%). 87 Rb has a half-life of 4.92 × 1010 years. It readily substitutes for potassium in minerals, and is therefore fairly widespread. 87 Rb has been used extensively in dating rocks; 87 Rb ...
The cent, the United States of America one-cent coin (symbol: ¢ ), often called the " penny ", is a unit of currency equaling one one-hundredth of a United States of America dollar. It has been the lowest face-value physical unit of U.S. currency since the abolition of the half-cent in 1857 (the abstract mill, which has never been minted ...
The indicators used in the 2022 report were life expectancy at birth; expected years of schooling for children; mean years of schooling for adults; and gross national income per capita. The indicators are used to create a health index, an education index and an income index, each with a value between 0 and 1.
Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. [ 2] The global population has grown from 1 billion in 1800 to 8.1 billion in 2024. [ 3] The UN projected population to keep growing, and estimates have put ...
Only 87 Sr is radiogenic; it is produced by decay from the radioactive alkali metal 87 Rb, which has a half-life of 4.88 × 10 10 years (i.e. more than three times longer than the current age of the universe).
Bismuth-209 was long thought to have the heaviest stable nucleus of any element, but in 2003, a research team at the Institut d’Astrophysique Spatiale in Orsay, France, discovered that 209 Bi undergoes alpha decay with a half-life of ≈19 exayears (1.9×10 19, or 19 quintillion years), [3] [4] over 10 9 times longer than the estimated age of the universe. [5]